Resist sidewall angle impacts photoprocess performance on topography. For example, a sloped sidewall results in a large critical dimension (cd) change in a resist line going over a step in the substrate. Resist sidewall angle also impacts subsequent pattern transfer steps. For example, a sloped resist sidewall can result in a sloped sidewall in the etched material. Sometimes this is desirable, but often it is not. Currently, the most common method for measuring sidewall angles of patterned materials is with a scanning electron microscope (SEM). This, however, is labor intensive and time consuming.
A need remains for a method of measuring resist sidewall angle.